Knife structure for a knife reel

ABSTRACT

A knife structure for the knife reel of a turf conditioning apparatus which is mounted upon a square sectioned reel shaft. The knife structure uses replaceable sickle blades. The base of each blade is abutted against an end of a rectangular spacer plate so that the two blades extend from the plate in spaced opposition. A cover plate at each side of the spacer plate overlies the spacer plate and the base edge of each of the blades so that the spacer plate and the base portions of the blades are sandwiched between the cover plates. Holes at each end of the cover plates register with holes at the base of the cutter blades to receive bolts, and the assembly is secured together by tightening these bolts with nuts. A square opening extends through the cover plates and the spacer plate at the center of the knife structure, this opening fitting securely upon the square shaft. Tubular spacers threaded upon the shaft hold the assembly in position.

United States Patent [1 1 [111 3,734,197 Zehrung, Jr. [4 1 May 22, 1973I541 KNIFE STRUCTURE FOR A KNIFE REEL Inventor: Claude D. Zehrung, Jr.,Englewood,

Colo.

Rental Equipment Manufacturing Co., Englewood, Colo.

Filed: July 22, 1971 Appl. No.1 165,235

Assignee:

References Cited UNITED STATES PATENTS Benson et al.

Carter ..56/295 Fishaw ..56/294 Vasconcellos ..56/295 FOREIGN PATENTS ORAPPLICATIONS 831,727 3/1960 Great Britain 1 72/21 PrimaryExaminer-Robert E. Pullfrey Assistant Examiner-R. T. RaclerAttorney-Horace B. Van Valkenburgh et al.

[57] ABSTRACT A knife structure for the knife reel of a turfconditioning apparatus which is mounted upon a square sectioned reelshaft. The knife structure uses replaceable sickle blades. The base ofeach blade is abutted against an end of a rectangular spacer plate sothat the two blades extend from the plate in spaced opposition. A coverplate at each side of the spacer plate overlies the spacer plate and thebase edge of each of the blades so that the spacer plate and the baseportions of the blades are sandwiched between the cover plates. Holes ateach end of the cover plates register with holes at the' base of thecutter blades to receive bolts, and the assembly is secured together bytightening these bolts with nuts. A square opening extends through thecover plates and the spacer plate at the center of the knife structure,this opening fitting securely upon the square shaft. Tubular spacersthreaded upon the shaft hold the assembly in position.

7 Claims, 10 Drawing Figures PATEmm-a'xzms 73 l 97 sum 1 OF 2 Fig. 9

INVENTOR.

Claude D. Zehrung Jt 'Q- 7 Fig. 8 BY ATTORNEYS PATENTEB M22 1975 MT 2[1F 2 INVENTOR. Claude D Zehrung Jr BY VM flMg ATTORNEYS KNIFE STRUCTUREFOR A KNIFE REEL The present invention relates to apparatus which usesflails or knives to condition turf by removing dead grass, cuttingrunners and tilling and aerating the soil. The invention relates, moreparticularly, to rotary knives for such apparatus.

A turf conditioning apparatususing rotary flails or knives is commonlymounted upon a vehicle which carries its power supply, usually agasoline engine. This engine drives a shaft which is mounted in thevehicle transversely to the normal direction of vehicle travel, and theshaft carries an array of swinging flails or fixed knives to strike theturf and the ground surface as the shaft rotates. In many units thisshaft and the flails or knives mounted upon it constitute a removableand replaceable sub-assembly which is commonly referred to as a flailreel or a knife reel. The present invention concerns improvements in theconstruction of knives for such a knife reel; accordingly, the inventionwill be called A KNIFE STRUCTURE FOR A KNIFE REEL. The same is hereindescribed as being for turf conditioning apparatus, but it is to beunderstood that the invention is not to be limited by such a specificapplicatlon.

An object of the invention is to provide a novel and improved knifestructure for a knife reel which is so]- idly and securely carried uponthe reel shaft and which will effectively remove dead grass, cut theturf and cut into the soil below the turf as the shaft is rotated.

Another object of the invention is to provide a knife structure for aknife reel which has easily replaceable cutter blades and which may useeither standard, readily available mower blades as replacements or, ifdesired, any special type of blade for specific purposes.

Another object of the invention is to provide a novel and improved knifestructure for a knife reel, wherein an array of knives may be carriedupon the reel at various desired spacings along the reel and at suitableradial positions about the reel.

Other objects of the invention are to provide a novel and improvedstructure of a knife for a turf cutting reel which is simple, versatile,economical, rugged and durable.

With the foregoing and other objects in view, of all which more fullyhereinafter appear, my invention comprises certain constructions,combinations and arrangements of parts and elements as hereinafterdescribed, defined in the appended claims and illustrated in theaccompanying drawings, in which:

FIG. 1 is a diagrammatic side elevational view of a vehicle forconditioning turf with portions of the frame of the vehicle broken awayto show the improved knife reel.

FIG. 2 is a perspective view of a knife reel such as may be used in thevehicle shown at FIG. 1 and which carries knives constructed accordingto the present invention.

FIG. 3 is a front view of a fragment of the knife reel and an edge viewof a knife thereon, as taken from the indicated arrow 3 at FIG. 2.

FIG. 4 is a sectional view of the reel shaft and spacer thereon, and aside view ofa knife on the shaft, as taken from the indicated line 4-4at FIG. 3.

FIG. 5 is a sectional view of the knife structure and of the reel shaft,as taken from the indicated line 5-5 at FIG. 3.

FIG. 6 is an exploded view of the components forming a knife structureand also a fragmentary portion of the reel shaft wherein the knifestructure is mounted.

FIG. 7 is an edge view of a knife blade per se, but showing a modifiedform from that illustrated at FIGS. 3 to 6.

FIG. 8 is a side elevational view of the blade shown at FIG. 7, as fromthe indicated arrow 8 at FIG. 7.

FIG. 9 is a plan view of the blade as from the indicated arrow 9 at FIG.7.

FIG. 10 is a fragmentary sectional detail as taken from the indicatedline 10-l0 at FIG. 4, but on an enlarged scale and showing a modifiedconstruction of the connection of a blade to the knife structure.

Referring more particularly to the drawing, a turf conditioningapparatus is depicted at FIG. 1. This unit is a wheel-mounted vehiclehaving a body structure 20 in the general form of an invertedrectangular pan with the wheel 21 thereof being mounted upon each sideof the body. A gasoline driven engine 22 upstands from the deck of thebody. The engine may drive the vehicle in any suitable manner, and itscontrols are ordinarily located on a push handle 23. Such a drive andthe controls therefor are not shown since they are conven tional. Theengine 22 also drives a knife reel 25 having its shaft 26 transverselydisposed with respect to the normal direction of movement of thevehicle.

The knife reel 25 is carried within the body 20. Its shaft 26 protrudesthrough one side of this body, and it is operatively connected to theengine 22 by a belt 27 and pulleys 28 in a direct-connectionarrangement. The shaft 26 carries an array of knife assemblies whichrotate with the rotation of the shaft 26. In preferred construction,this shaft 26 is mounted upon a wide U- shaped bracket 29 which isconveniently fitted into the body of the turf conditioning vehicle asindicated at FIG. 1. Each end of the shaft is mounted in bearings, notshown, which are mounted on the legs of the bracket to carry pulleys 28which, in turn, connect with the belt 27 extending from the engine 22.

As best illustrated at FIG. 6, the major reach of transverse reel shaft26 is square in section, but its end portions are turned as at 20 to fitupon support bearings, and to carry a pulley 28. Also, one end of theshaft is threaded as indicated at 31, FIG. 6, to receive a take-up nutto provide a tight assembly when all components are mounted in position.The array of knives carried upon this square shaft have center openings33 so they snugly fit upon the shaft 26. The number of knives to be usedis optional, and in the unit shown at FIG. 2, ten knives K are providedwhich are positioned across the shaft and are held in place by shorttubular spacers 34.

Each knife structure K is made up as an assembly of components includinga rectangular spacer plate 35 having a square opening 33a at its centerto fit tightly upon the shaft 26. A triangular knife blade 36 is abuttedagainst each end of this spacer plate 35 to extend outwardly therefromand the opposing blades are held in position by a pair of cover plates37 which lie against the sides of the spacer plate, which include squareopenings 33b at their centers and which extend a short distance beyondthe ends of the spacer plate to overlie and to connect with the blades36, as hereinafter further described.

Each triangular knife blade 36 is preferably a standard 3-inch sickleblade of the type commonly used in powered mowers. Such blades, of hard,tempered steel,

are standardized so they may be easily replaced. Thus, the spacer plate35 and cover plates 37 are proportioned to accommodate the pair ofopposing blades of a standard size. Each blade 36 is generallytriangular with a flat, squared base edge 38, and with short side edges39 perpendicular to the base edge to establish the width of the bladewhich, in the type selected, is three inches. The sides converge fromthe short side edges 39 as sharp, beveled side cutting edges 40 whichextend to a blunted apex point 41 at the center of the blade. Tocomplete the unit, two mounting holes 42 are located adjacent to thebase, with a hole being adjacent to each side edge 39.

The spacer plate 35 has the same width as the blades 36 which abutagainst its opposite sides. The opposing ends 43 of this spacer plateare thus adapted to hold the ends 38 of the blades 36 in place, and thelength of the spacer plate is such that the blades are set apart aselected distance as established by the size of the knife reel. Thethickness of this spacer plate is the same as, or slightly less than,the thickness of the blades to permit the cover plates 37 to tightlygrip each blade when all components are assembled and tightly tiedtogether.

The cover plates 37 also have the same width as the spacer plate 35 andthe blades 36. The length, however, exceeds the length of the spacerplate to permit each end edge 44 to overlap the base of a blade 36. Apair of holes 42a at each end of each spacer plate register with theholes 42 in the blades wherever the components forming the knifestructure are positioned for assembly with a blade extending from eachend of the structure. Thus, whenever the cover plates 37 sandwich thespacer plate and blades between them, the assembly may be completed byfitting bolts 45 into the holes 42 and 42a, securing these bolts withnuts 46, and tying the assembly together. These bolts 45 are subject toconsiderable impacting shear and bearing stresses when the knife reel israpidly rotating with the blades which are striking the turf. Therefore,each is preferably hardened and formed with a solid shank 47 closelyfitting the holes 42a in the cover plates, and the hole 42 in the blade.

FIG. 10 shows an alternate arrangement for bolting the plates togetherwhen the knife structure is subjected to abuse. The holes 42 and 42a areenlarged, and a tubular sleeve 48 is fitted therein with the bolt beingfitted into the sleeve, and with washers 49 at each side ofthe sleeve tohold it in place. As such, the sleeve provides greater resistance toshear and bearing impacts when the knife structure is in use.

The manner in which the array of knife structures K is mounted upon ashaft 26 to form a reel is simple and straightforward. The knives K arefitted into position upon the square shaft in an alternating arrangementwith spacers 34 between them. Suitable spacers 34 are provided at theends of the shaft to hole the array of knives in properly spacedpositions upon the shaft between the support bearings which are notshown.

Variations to this arrangement above described are possible. As shown atFIG. 2, the knives K are arranged on the shaft 90 apart, and the holes33 are preferably aligned on the axes of the spacer plate and coverplates. However, a different sequence of spacing about the shaft ispossible. For example, where an arrangement of knives at 45 degrees isdesired, certain of the knife structures may have the square centeropening 33 oriented at 45 degrees with respect to the axis of the knifestructure, as indicated by the broken lines 33' at FIG. 5. Anotherobvious manner to obtain yet another arrangement involves the use of ahexagonal shaft and a hexagonal opening in each knife structure Kinstead of the square opening 33.

In lieu of the flat triangular blades 36, blades of various types may beused, and FIGS. 7 to 9 show a modified blade 36a which has an out-turnedend 50. The blade is essentially triangular, having a base 38, shortsidewall portions 39 at each side of the base, a converging beveled sidecutting edge 40a at each side which converges to a flat apex point 41a,but with the end portion 50 of the blade adjacent to the apex pointbeing turned outwardly. The result is that the end of the blade cuts aswath in turf. Accordingly, this type of blade is useful for scalpingturf and for similar purposes.

I have now described my invention in considerable detail; however, it isobvious that others skilled in the art can devise and build alternateand equivalent constructions which are nevertheless within the scope andspirit of the invention. Hence, I desire that my protection be limited,not by the constructions illustrated and described, but only by theproper scope of the appended claims.

I claim:

1. A knife structure for the knife reel of a turf conditioning apparatusand the like, wherein the knife reel includes a rotatable shaft having asection formed as a simple, regular polygon, and wherein the knifestructure comprises, in combination therewith:

a. a pair of blades formed as flat members, with each blade having abase edge and a side cutting edge;

b. a rectangular spacer plate having: a thickness approximating but notexceeding the thickness of the blades, opposite ends against which thebase edges of the blades may abut with the blades extending therefrom inspaced opposition to each other, and a hole at the center of the spacerplate formed as a simple regular polygon fitting upon the aforesaidshaft;

c. a pair of cover plates arranged to lie against the sides of thespacer plate having a length exceeding the length of the spacer platesufficiently to extend beyond each end thereof to lap against portionsof blades abutted against the spacer plate, and a hole at the center ofeach cover plate in registration with the spacer plate hole and sized tofit upon the aforesaid shaft;

d. a means to secure each blade to and between the extended lappingportions of the cover plates when the bases of the blades are abuttedagainst the ends of the spacer; and

e. said securing means includes at least two spaced, aligned holesarranged to pass through the lapping portions of the cover plates andthe respective blade, said holes being located near the base edge ofsaid blade, and a removable fastening pin means positioned through eachaligned hole to retain said blade in abutted position against saidspacer plate whereby the impact forces upon the side cutting edge aretransferred to the abutting surface by fulcrum effect about the pinnearest the cutting edge.

2. In the organization defined in claim 1, wherein the polygon definedby the sections of the shaft and the aforesaid holes in the spacer plateand in the cover plates is a square with the sides of all of the holesbeing apparatus or the like comprising a rotor arranged to be mountedfor rotation about its longitudinal axis and a plurality of cuttingknives mounted on and spaced longitudinally along said rotor, saidcutting knife includes:

oriented upon the respective plates in the same manner to permit them tolie together when upon the shaft.

3. In the organization defined in claim 1, wherein the 4. In theorganization defined in claim 3 wherein the apex portion of the blade isbent laterally with respect to the rest of the blade to cut a widepattern in the turf.

5. A knife reel assembly for use in turf conditioning a. blade meanshaving a flat blade member which includes a base edge and a side cuttingedge; 1

b. spacer means including an elongated flattened member having means formounting said member on said rotor for rotation therewith and abuttingmeans disposed at one end of said member and arranged to abut againstthe base edge of the blade means whereby the blade means extendsradially outward from said rotor;

c. cover means comprising at least two generally flat members fixedlypositioned on each side of the spacer means so as to overlap at least aportion of said blade means; and

d. means for securing said cover means to said blade means, saidsecuring means including at least two removable fastener means insertedthrough aligned holes through said cover means and said blade means,said aligned holes being located near the base edge of said blade meanswhereby the base edge is held rigidly against the abutting means duringrotation so that the impact forces on the cutting edge will betransferred to the abutting means.

6. A knife reel assembly as defined in claim 5,

wherein:

said abutting means includes surfaces at each end of the elongatedflattened member and the mounting means comprises an aperture providedat the midpoint of said member;

said blade means include two flat blade members, the base edge of eachblade member arranged contiguous to an abutting edge on said spacermeans, and said cover means is arranged to overlap a portion of eachblade member whereby said blades are secured against the abuttingsurfaces of said spacer means.

7. A knife reel assembly as defined in claim 6,

wherein:

lines extended along said cutting edge and said base edge of said blademembers form an acute angle.

1. A knife structure for the knife reel of a turf conditioning apparatusand the like, wherein the knife reel includes a rotatable shaft having asection formed as a simple, regular polygon, and wherein the knifestructure comprises, in combination therewith: a. a pair of bladesformed as flat members, with each blade having a base edge and a sidecutting edge; b. a rectangular spacer plate having: a thicknessapproximating but not exceeding the thickness of the blades, oppositeends against which the base edges of the blades may abut with the bladesextending therefrom in spaced opposition to each other, and a hole atthe center of the spacer plate formed as a simple regular polygonfitting upon the aforesaid shaft; c. a pair of cover plates arranged tolie against the sides of the spacer plate having a length exceeding thelength of the spacer plate sufficiently to extend beyond each endthereof to lap against portions of blades abutted against the spacerplate, and a hole at the center of each cover plate in registration withthe spacer plate hole and sized to fit upon the aforesaid shaft; d. ameans to secure each blade to and between the extended lapping portionsof the cover plates when the bases of the blades are abutted against theends of the spacer; and e. said securing means includes at least twospaced, aligned holes arranged to pass through the lapping portions ofthe cover plates and the respective blade, said holes being located nearthe base edge of said blade, and a removable fastening pin meanspositioned through each aligned hole to retain said blade in abuttedposition against said spacer plate whereby the impact forces upon theside cutting edge are transferred to the abutting surface by fulcrumeffect about the pin nearest the cutting edge.
 2. In the organizationdefined in claim 1, wherein the polygon defined by the sections of theshaft and the aforesaid holes in the spacer plate and in the coverplates is a square with the sides of all of the holes being orientedupon the respective plates in the same manner to permit them to lietogether when upon the shaft.
 3. In the organization defined in claim 1,wherein the blade is a triangular member with each side cutting edgeconverging from the base to a blunted apex point.
 4. In the organizationdefined in claim 3 wherein the apex portion of the blade is bentlaterally with respect to the rest of the blade to cut a wide pattern inthe turf.
 5. A knife reel assembly for use in turf conditioningapparatus or the like comprising a rotor arranged to be mounted forrotation about its longitudinal axis and a plurality of cutting knivesmounted on and spaced longitudinally along said rotor, said cuttingknife includes: a. blade means having a flat blade member which includesa base edge and a side cutting edge; b. spacer means including anelongated flattened member having means for mounting said member on saidrotor for rotation therewith and abutting means disposed at one end ofsaid member and arranged to abut against the base edge of the blademeans whereby the blade means extends radially outward from said rotor;c. cover means comprising at least two generally flat members fixedlypositioned on each side of the spacer means so as to overlap at least aportion of said blade means; and d. means for securing said cover meansto said blade means, said securing means including at least tworemovable fastener means inserted through aligned holes through saidcover means and said blade means, said aligned holes being located nearthe base edge of said blade means whereby the base edge is held rigidlyagainst the abutting means during rotation so that the impact forces onthe cutting edge will be transferred to the abutting means.
 6. A knifereel assembly as defined in claim 5, wherein: said abutting meansincludes surfaces at each end of the elongated flattened member and themounting means comprises an aperture provided at the mid-point of saidmember; said blade means include two flat blade members, the base edgeof each blade member arranged contiguous to an abutting edge on saidspacer means, and said cover means is arranged to overlap a portion ofeach blade member whereby said blades are secured against the abuttingsurfaces of said spacer means.
 7. A knife reel assembly as defined inclaim 6, wherein: lines extended along said cutting edge and said baseedge of said blade members form an acute angle.